if err == nil {
			if test.error != "" {
				t.Errorf("#%d: %q: expected error %q; got none", i, test.input, test.error)
			}
			continue
		}
		if !strings.Contains(err.Error(), test.error) {
			t.Errorf("#%d: expected error %q; got %q", i, test.error, err)
			continue
		}
	}
}

func runBadTest(i int, test badExprTest, t *testing.T) (err error) {

pkg syscall (freebsd-riscv64), func Setegid(int) error #53466
pkg syscall (freebsd-riscv64), func Seteuid(int) error #53466
pkg syscall (freebsd-riscv64), func Setgid(int) error #53466
pkg syscall (freebsd-riscv64), func Setgroups([]int) error #53466
pkg syscall (freebsd-riscv64), func Setlogin(string) error #53466
pkg syscall (freebsd-riscv64), func Setpgid(int, int) error #53466

	f     *File
	desr  io.Reader // if non-nil, where to read the data descriptor
	err   error     // sticky error
}

func (r *checksumReader) Stat() (fs.FileInfo, error) {
	return headerFileInfo{&r.f.FileHeader}, nil
}

func (r *checksumReader) Read(b []byte) (n int, err error) {
	if r.err != nil {
		return 0, r.err
	}
	n, err = r.rc.Read(b)
	r.hash.Write(b[:n])

	scanner := bufio.NewScanner(strings.NewReader("gopher"))
	for scanner.Scan() {
		fmt.Println(len(scanner.Bytes()) == 6)
	}
	if err := scanner.Err(); err != nil {
		fmt.Fprintln(os.Stderr, "shouldn't see an error scanning a string")
	}
	// Output:
	// true
}

// Use a Scanner to implement a simple word-count utility by scanning the
// input as a sequence of space-delimited tokens.
func ExampleScanner_words() {

func addProblem(url, errmsg string) {
	msg := fmt.Sprintf("Error on %s: %s (from %s)", url, errmsg, linkSources[url])
	if *verbose {
		log.Print(msg)
	}
	problems = append(problems, msg)
}

func crawlLoop() {
	for url := range urlq {
		if err := doCrawl(url); err != nil {
			addProblem(url, err.Error())
		}
	}
}

func doCrawl(url string) error {
	defer wg.Done()

pkg archive/tar, type FileInfoNames interface { Gname, IsDir, ModTime, Mode, Name, Size, Sys, Uname } #50102
pkg archive/tar, type FileInfoNames interface, Gname() (string, error) #50102
pkg archive/tar, type FileInfoNames interface, IsDir() bool #50102
pkg archive/tar, type FileInfoNames interface, ModTime() time.Time #50102
pkg archive/tar, type FileInfoNames interface, Mode() fs.FileMode #50102
pkg archive/tar, type FileInfoNames interface, Name() string #50102

		usage()
	}

	var zb bytes.Buffer
	zw := zip.NewWriter(&zb)
	seen := make(map[string]bool)
	err := filepath.WalkDir(".", func(path string, d fs.DirEntry, err error) error {
		if d.IsDir() {
			return nil
		}
		data, err := os.ReadFile(path)
		if err != nil {
			log.Fatal(err)
		}
		if strings.HasSuffix(path, ".zip") {
			log.Fatalf("unexpected file during walk: %s", path)

[`x509usepolicies` setting.](/pkg/crypto/x509/#CreateCertificate).


### Go 1.21

Go 1.21 made it a run-time error to call `panic` with a nil interface value,
controlled by the [`panicnil` setting](/pkg/builtin/#panic).

Go 1.21 made it an error for html/template actions to appear inside of an ECMAScript 6
template literal, controlled by the

pkg os, func CopyFS(string, fs.FS) error #62484...

The [DNSError] type now wraps errors caused by timeouts or cancellation.
For example, `errors.Is(someDNSErr, context.DeadlineExceedeed)`